List of top Physics Questions

Assuming the earth to be a sphere of uniform density, the acceleration due to gravity inside the earth at a distance of $r$ from the centre is proportional to
Assume that a neutron breaks into a proton and an electron. The energy released during this process is : (Mass of neutron $= 1.6725 ??10^{-27}\, kg$, Mass of proton $= 1.6725 ??10^{-27}\, kg$, Mass of electron $= 9 ??10^{-31}\, kg$ )
An object $2.4\, m$ in front of a lens forms a sharp image on a film $12\, cm$ behind the lens. A glass plate $1\, cm$ thick, of refractive index $1.50$ is interposed between lens and film with its plane faces parallel to film. At what distance (from lens) should object shifted to be in sharp focus on film ?
An insect crawls up a hemispherical surface very slowly. The coefficient of friction between the insect and the surface is 1/3. If the line joining the centre of the hemispherical surface to the insect makes an angle a with the vertical, the maximum possible value of a so that the insect does not slip is given by
An artificial satellite moving in a circular orbit around the earth has a total (kinetic $+$ potential) energy $E_0$. Its potential energy is
A wooden wheel of radius R is made of two semicircular parts (see figure). The two parts are held together by a ring made of a metal strip of cross sectional area S and length L. L is slightly less than 2?R. To fit the ring on the wheel, it is heated so that its temperature rises by ?T and it just steps over the wheel. As it cools down to surroundifng temperature, it presses the semicircular parts together. If the coefficient of linear expansion of the metal is $R$, and its Young's modulus is Y, the force that one part of the wheel applies on the other part is :
A thin liquid film formed between a U-shaped wire and a light slider supports a weight of $1.5 ??10^{-2}\, N$ (see figure). The length of the slider is $30\, cm$ and its weight negligible. The surface tension of the liquid film is :
A spherical drop of capacitance 1 $\mu$F is broken into eight drops of equal radius. Then, the capacitance of each small drop is
A liquid in a beaker has temperature $\theta(t)$ at time $t$ and $\theta_0$ is temperature of surroundings, then according to Newton's law of cooling the correct graph between $log_{e}\left(\theta-\theta_{0}\right)$ and $t$ is :
A hypothetical atom has only three energy levels. The ground level has energy, $E_1 = - 8$ eV. The two excited states have energies, $E_2 = - 6$ eV and $E_3 = - 2$ eV. Then which of the following wavelengths will not be present in the emission spectrum of this atom?
A goods train accelerating uniformly on a straight railway track, approaches an electric pole standing on the side of track. Its engine passes the pole with velocity $u$ and the guard?s room passes with velocity $v$. The middle wagon of the train passes the pole with a velocity.
A given ideal gas with $\gamma = \frac{C_{p}}{C_{v}} = 1.5$ at a temperature $T$. If the gas is compressed adiabatically to one-fourth of its initial volume, the final temperature will be
For which colour, angle of d eviation is minimum?
If $\upsilon_{s}$ is the velocity of sound in air and $\upsilon$ is the $rms$ value, then
An electron of charge $e$ is orbiting in a circular path of radius $r$ with a uniform speed $v$. Its magnetic moment will be
A diatomic molecule is made of two masses $m_1$ and $m_2$ which are separated by a distance $r$. If we calculate its rotational energy by applying Bohr?'s rule of angular momentum quantization, its energy will be given by : ($n$ is an integer)
A coil is suspended in a uniform magnetic field, with the plane of the coil parallel to the magnetic lines of force. When a current is passed through the coil it starts oscillating; it is very difficult to stop. But if an aluminium plate is placed near to the coil, it stops. This is due to :
A circular hole of diameter $R$ is cut from a disc of mass $M$ and radius $R$; the circumference of the cut passes through the centre of the disc. The moment of inertia of the remaining portion of the disc about an axis perpendicular to the disc and passing through its centre is
A charge $Q$ is uniformly distributed over the surface of non-condcting disc of radius $R$. The disc rotates about an axis perpendicular to its plane and passing through its centre with an angular velocity $\omega $. As a result of this rotation a magnetic field of induction $B$ is obtained at the centre of the disc. if we keep both the amount of charge placed on the disc and its angular velocity to be constant and vary the radius of the disc then the variation of the magnetic induction at the centre of the disc will be represented by the figure :
A boy can throw a stone up to a maximum height of $10\,m$. The maximum horizontal distance that the boy can throw the same stone up to will be :
A point particle is held on the axis of a ring of mass $m$ and radius rat a distance $r$ from its centre $C$. When released, it reaches $C$ under the gravitational attraction of the ring. Its speed at $C$ will be
An air column in a pipe, which is closed at one end, will be in resonance with a vibrating tuning fork of frequency $264\, Hz$ if the length of the column in cm is (velocity of sound = $330\, m/s$)
The terminal velocity of a small sphere of radius a in a viscous liquid is proportional to
The figure shows a combination of two NOT gates and a NOR gate. The combination is equivalent to a
The counting rate observed from a radioactive source at $t = 0$ was $1600$ counts $s^{-1}$, and $t = 8 \,s$, it was $100$ counts $s^{-1}$. The counting rate observed as counts $s^{-1}$ at $t = 6$ s will be